Process and device for moving and positioning sheets of glass

ABSTRACT

In a system for cutting glass sheets into shapes there is at least one cutting site (A, B). In order to align the glass sheet which is to be cut or the glass sheet shape into a defined position, on the edge of the tables I and II there are contact edges ( 21, 44, 45 ). In order to move the glass sheets and the glass sheet shapes into contact with the contact edges ( 21, 44, 45 ) the tables I, II are aligned sloping down toward the contact edges ( 21, 44, 45 ) so that the glass sheets and glass sheet shapes slide on air cushions produced between the glass sheets or glass sheet shapes and the tables (I, II) in contact with the contact edges ( 21, 44, 45 ). The glass sheets or glass sheet shapes which adjoin the contact edges ( 21, 45 ) are coupled by force-fit to the conveyor belts ( 20 ) which are provided in the area of the contact edges ( 21, 45 ) and then moved to the cutting site (A, B) which is located following the table (I, II). When there are two cutting sites (A, B) the table ( 11 ) can be inclined between the two cutting sites (A, B) such that the intersection point which is used as the reference point ( 43 ) between the two contact edges ( 44, 45 ) is the lowest point of the table (II).

The invention relates to a process and a device for moving andpositioning glass sheets in conjunction with the cutting of sheets ofglass (glass cutting). The glass sheets under consideration here are forexample float glass and laminated glass. In known devices for cuttingglass sheets (“glass cutting tables”) as are known for example from EP 0564 758 A, to move and position the glass sheets conveyor belts and/orconveyor rollers are used which are recessed into the support surfacesof the glass cutting tables and which are raised over the supportsurface when a glass sheet is to be transported. These conveyor beltsare also known in devices for cutting laminated glass (WO 95/16640 A=EP0 708 741 A).

To move glass sheets on glass cutting tables, providing drivers for theglass sheets on the cutting bridge is furthermore known. Vacuums headsmounted on the cutting bridge (EP 0 192 290 A), or drivers which can beplaced on one edge of a glass sheet (US-A-5,944,244) are known.

Glass sheets must be positioned on glass cutting tables not onlyaccurately, but also promptly. This is not possible with the knowndevices or is possible only with considerable effort. Here it must beconsidered that glass sheets with a weight of up to 1000 kg (laminatedglass) must be moved and positioned accurately. Furthermore, it can beconsidered that the glass sheets on the glass cutting tables must bemoved in different directions, for example to make X and Y cuts.

The object of the invention is to devise a process and a device of theinitially mentioned type which allow accurate, prompt and simplemovement of glass sheets (float glass and laminated glass) in theirpositioning and which do not require complex conveying means for movingand positioning the glass sheets to be cut or glass sheet shapes to befurther cut. This object is achieved as claimed in the invention with aprocess which has the features of claim 1.

With respect to the device, this object is achieved with a device whichhas the features of the main apparatus claim.

Preferred and advantageous developments of the process as claimed in theinvention on the one hand and the device as claimed in the invention onthe other are the subject matter of the dependent claims.

The process as claimed in the invention takes place such that thesupport surface on which the glass sheet which is to be moved lies istilted such that it slopes in the direction to a defined reference line(contact edge) and the glass sheet which lies on it slides up to thisreference line (contact edge). The glass sheet or a glass sheet shapeare then positioned by adjoining at least one reference line (contactedge).

By choosing the angle of the tilt of the support surface and/or bychoosing the coefficient of friction between the glass sheet and thesurface of the support surface, glass sheets of varied size and weightcan be taken into account.

In one preferred embodiment the glass sheets slide on an air cushionwhich is formed between the support surface and the glass sheet. An aircushion as the sliding surface for glass sheets also has the advantagethat the friction between the glass sheet and the support surface can beset by setting the pressure with which air flows out of the air cushionopenings in the support surface to the value which is desired at thetime and if necessary can be changed during the movement of the glasssheet. This offers for example the possibility of reducing the frictionat the start of the movement of the glass sheet and of increasing thefriction before the end of the movement of the glass sheet, for examplewhen it is approaching the reference line (contact edge) by lowering thepressure of the air which forms the air cushion.

In the procedure as claimed in the invention in one embodiment a glasssheet which rests on at least one contact edge which forms the referenceline is moved by force-fitted coupling of the glass sheet to a conveyormeans by defined distances in order to feed it in a defined manner tothe cutting point at which the glass sheet is cut (scratched).

The process as claimed in the invention also makes it possible tocontinue to move and position the cut glass sheets, especially parts ofglass sheets which are obtained after cutting the traverses (X cuts) andto feed them accurately positioned to the next cutting point where Ycuts are made.

The glass sheet shapes are positioned preferably such that a glass sheetshape is moved by inclining the support surface after the first cuttingsite with one of its comers at a reference point which is defined forexample by two contact edges which are at an angle of 90° to oneanother. To the extent the device is affected, the support surfacesbefore and after the cutting devices, therefore the feed table of thefirst cutting device (for X cuts), the second table with which the glasssheet shapes after the first cut (X cut) are moved to the second cuttingdevice (for Y cuts), and finally the delivery table in the direction toat least one contact edge is tilted down or optionally is madeadditionally to be able to tilt so that they are aligned at an angle tothe horizontal.

Furthermore in the device as claimed in the invention, on the edge ofeach table at least one contact edge is formed as the reference linewhich is generally aligned normally to the downstream cutting site. Thisreference line (contact edge) is for example a conveyor belt. A glasssheet which is to be moved by the conveyor belt along the contact edgeor a glass sheet shape is coupled to the respective conveyor belt. Thiscoupling takes place for example via at least one coupling suction headwhich is movably guided on a rail parallel to the conveyor belt and canbe loaded in the direction to the conveyor belt after being applied tothe glass sheet, so that between the conveyor belt and the glass sheetfrictional adherence is formed which makes it possible to move the glasssheet by sliding using the conveyor belt on the support surface. Thereis no separate drive for the carriage which bears the coupling suctionhead to move it along the contact edge.

Other details and features as well as advantages of the invention derivefrom the following description of one preferred embodiment with respectto the drawings in which a cutting unit (for laminated glass) is shown.

FIG. 1 shows a (laminated) glass cutting unit in an overhead view,

FIG. 2 shows a (laminated) glass cutting unit in an oblique view,

FIG. 3 schematically shows a suction head for coupling a glass sheet ina conveyor belt,

FIG. 4 shows a modified embodiment with a second conveyor means in thearea in front of the first cutting site, and

FIG. 5 schematically shows a suction head on the conveyor device fromFIG. 4.

In the embodiments shown in FIGS. 1 to 5 the illustrated unit forcutting laminated glass is made. This means that at each cutting sitethere are not only means for scratching the laminated glass fromoverhead and underneath, but also means for breaking the scratchedlaminated glass and for cutting the plastic film between the two panesof glass of the laminated glass.

If the unit as claimed in the invention is designed as one for cuttingof normal glass, it is generally such that the scratching of the glasssheet along the cutting contour takes place separately from the breakingof the scratched glass sheets which is carried out at the cutting sitesA, B into glass shapes as is described for example in US 5 857 603 A.The cutting unit for laminated glass on the one hand has a table I onwhich glass sheets are placed in the direction of the arrow 10. Thetable I can also be folded up around its inlet-side edge 11 so that onit glass sheets from a glass sheet storage are set up on support hooks12 on this edge 11 and then by folding back the table 1 into the initialposition which is essentially horizontal they can be shifted.

On the edge 13 which is opposite the edge 11 which is equipped with thehook 12 the table I adjoins a stationary strip 14.

The table I and the stationary strip 14 are preferably made as an aircushion table. i.e. there are openings 15 distributed over their supportsurfaces, out of which compressed air flows so that a glass sheet lyingon the table I floats on an air cushion.

The support surface of the Table 1 can be equipped for example withrollers like the tables II and II still to be explained on its supportsurface.

The table I, more accurately its support surface, is tilted in its baseposition (initial position) down towards the contact edge 12 or can betilted around the edge 13 which lies in the area of the joint 16 betweenthe table I and the strip 14, in order to align the table I such that itis tilted down towards the contact edge 21. For example, the edge 11 ofthe table I equipped with the hooks 12 is higher or can be raised sothat the table I slopes down in the direction to the strip 14. A glasssheet which lies on the table I which is tilted beforehand or which isslanted by tilting slides on the table I, for example on an air cushion,“down” until it rests against the contact edge 21 which is formed by thestrand 22 of the conveyor belt 20. This contact edge 21 which is formedby the conveyor belt 20 forms a reference line and defines the locationof the glass sheet before it is moved to the cutting site A (cuttingdevice for glass or laminated glass).

If the support surface of the table I is tilted down towards the contactedge 21 in the initial position, the cutting device A is likewise tiltedand with the horizontal includes the same angle as the table I (it risesaway from the contact edge 21).

For reliable movement of the glass sheets on the table I (and the othertables II and III) small angles are sufficient, especially in aircushion tables. For example the edge 11 of the table I for a tablelength of 3–5 m can be roughly 2 cm higher than the edge 13. To move theglass sheet G on the table I in the direction to the cutting site A(compare FIG. 3), on a frame-mounted guide rail 25 which is alignedparallel to the conveyor belt 20 at least one carriage 30 on which atleast one suction head 31 is located is guided to be able to movefreely. The suction head 31 can be lowered for resting against the glasssheet G which lies on the support surface of the table I which is formedfor example by a felt layer 18 by a hydraulic motor 33 which isinstalled in the carriage 30 (arrow 34, FIG. 3) and can then be loadedusing another (arrow 35, FIG. 3) hydraulic motor 32 which is installedin the carriage 30 such that it pulls the glass sheet G against thestrand 22 of the conveyor belt 20 which forms the contact edge 21(reference line), by which the glass sheet G is coupled by force-fit tothe conveyor belt 20. By moving the conveyor belt 20 the glass sheet Gcan be moved on the table I, the friction being kept small by the aircushion of the table I. Just before the cutting point A on the table Ithere is a device 35 which detects the front edge of a glass sheetswhich is to be moved in order to define the reference position. Insteadof this device there can also be a simple stop which is moved away afterfixing the reference position, for example, lowered.

By moving the conveyor belt 20 with which the glass sheet is coupled viathe carriage 30 to the suction head 31 (there can be a separate drivefor the carriage 30, but it is generally not essential), the glass sheetis moved gradually to the cutting point A and X cuts (traverses) aremade in the glass sheet. The extent of feed of the glass sheet G to thecutting point A is detected with a path transducer which is coupled tothe conveyor belt 20, especially to its drive (incremental transducer)and based on the paths of the glass sheet which have been detected inthis way it is aligned relative to the cutting site A such that it iscut at the desired site. Before displacement of the glass sheet Gstarts, the table I is moved (tilted) into its location which isparallel to the alignment of the cutting site A.

The resulting glass strips (glass shapes) travel onto the table II. Thistable II is aligned in its base position which it assumes when executingthe cutting processes at the cutting site A in a plane with the table I,i.e. it is tilted to the horizontal by the same angle as Table I and thecutting device of the cutting site A, its also sloping down towards itscontact edge. This alignment of the table II can also be induced bylifting in the area of the its edge 40 which is adjacent to the cuttingsite A.

To convey a glass sheet shape away from the cutting site A the Table IIcan be inclined after each cutting process which is executed at thecutting site A such that the glass sheet shape on the table II which nowis also aligned sloping down away from the cutting site A or its edge 40slides out of the position located first directly to the right next tothe cutting site A into the position shown by the broken line in thedrawings. To do this the table II is raised in the area of the edge 40which is located next to the cutting site A.

In addition, the table II in the area of its edge 41 can also be raisedso that a glass sheet shape slides reliably on the table II in contactwith the two contact edges 44, 45 which are the two strands of theconveyor belts 20. Thus, the one comer of the glass sheet shape islocated at a reference point 43, in the example the intersection pointof the two contact edges 44, 45. At this instant the comer which formsthe reference point 43 is the lowest point of the table II since (as aresult) the corner of the table II has been raised.

A limit switch 47 establishes that a glass sheet shape rests on thereference edge 45. As soon as this is ascertained, the edge 40 which isadjacent to the cutting site A and also the edge 41 of the table IIwhich is normal thereto is lowered so that the table II is again alignedflush with the table I (lying in one plane).

In this embodiment, on the two contact edges 44, 45 of the table IIthere are conveyor belts 20 to which suction heads 31 on carriages 30(compare FIG. 3) are assigned, as was described above for Table 1. Thesuction head 31 on the contact edge 45 of the table II which is normalto the cutting site B and which is opposite (away from) and parallel tothe cutting site A is essential since via this carriage 30 with at leastone suction head 31 and the assigned conveyor belt 20 a glasssheet/glass sheet shape is gradually transported to the cutting site B(second cutting device) in order to execute the cutting processes in theY direction. There can also be a sensor 35 for detecting the forwardedge of the glass sheet shape in front of the cutting site B.

The conveyor belt 20 on the contact edge 44 of the table IIperpendicular to the cutting site A is designed essentially to supportthe motion of a glass sheet shape to the reference point 43, especiallywhen a glass sheet shape is to be tilted and should rest with one or twocomers on one or two conveyor belts 20 which form the contact edges 44,45. The carriage 30 which is provided in the embodiment from FIG. 1 atthe contact edge 41 with the suction head 31 is not absolutely necessaryand is generally not provided.

The table III which is located following the cutting site B is flushwith the table II and is first tilted rising away from the cutting siteB. It is important that the tables II and III lie in a (single) (forexample tilted) plane. In order to facilitate the removal of the glasssheet shape obtained after cutting by the cutting site B, the table IIIcan even be lowered after executing the cutting process in the area ofits edge 50. In the table III lifting strips 55 can also be recessed fortilting the glass sheet shape up. In the embodiment shown in FIG. 1 oneach of the contact edges 21 and 45 there are carriages 30 with at leastone suction head 31 (on the carriages 30 there can also be two suctionheads 31 each). It should be pointed out that this is a minimumrequirement since there can also be two or more carriages 30 with atleast one suction head 31 each on the contact edge 21 and/or the contactedge 45 in order to reliably move large and/or heavy glass sheets(compare FIG. 2). Generally however one carriage 30 per contact edge issufficient, especially when it engages in the middle area of the glasssheet and pulls it with relatively great force against the strand 22 ofthe respective conveyor belt 20 which forms the contact edge 21, 44, 45(reference line). If for example there are two carriages 30 (FIG. 2)with at least one suction head 31 each on the contact edges 21 and 45,they can also alternately engage glass sheets or glass sheet shapes.

In order to move the carriages 30 back into their initial position, therespective conveyor belt 20 is reversed, i.e. it runs in the oppositedirection and the carriage 30 is coupled via a driver to the conveyorbelt 20 by pressing the driver against the conveyor belt 20.

The movement of the tables, especially of the tables II and III,preferably takes place by movement of their frames which are locatedunderneath their support surfaces by hydraulic cylinders which aresupported on the bottom engaging the frames.

The operating sequence of the (laminated) glass cutting system withtables which can be inclined or which are inclined in their initialposition can be described by way of example with reference to FIG. 2 asfollows:

1. Table 1 is folded up around its edge 11 to accept a glass sheet froma stack 51 of glass sheets. The glass sheet is fixed on the table I viaseveral suction heads 52.

2. The table I is folded back into the initial position which slopesdown toward the contact edge 21. The glass sheet then slides on the aircushion toward the contact edge 21.

3. In this position the glass sheet is coupled by force-fit to theconveyor belt 20 by the suction head 31 on the carriage 30 (or by thesuction heads on the two carriages).

4. By actuating the conveyor belt 20 the glass sheet is advanced untilit is correctly aligned relative to the cutting device A for one cuttingprocess.

5. Then, when the tables I and II are flush with one another (both aretilted down towards the contact edge 21 and 44) the glass sheet shape iscut by the cutting device of the cutting site A. The resulting glasssheet shape (“traverse”) lies on the table II.

6. The table II is raised in the area of its edge 40 which is adjacentto the cutting site A so that it also slopes down obliquely toward thecontact edge 45.

7. The glass sheet shape moves (slides) on the table II into theposition in which it adjoins the contact edge 45 and the contact edge44.

8. By raising the table II in the area of its edge 41 adjacent to thecutting site B the table II is tilted such that its comer between thecontact edges 44, 45 is the lowest point. This ensures that the glasssheet shape with its comer is located at the reference point 43 andadjoins the contact edges 44, 45 with two edges which run towards itscomers.

9. When the glass sheet shape moves on the table II the conveyor belt 20is actuated in order to support this motion, especially when the glasssheet shape is inclined.

10. The glass sheet shape on the conveyor belt 20 in the area of thecontact edge 45 is fixed by force-fit by the suction head 31 on thecarriage 30 in the area of the contact edge 45, while it is located withits comer at the reference point 43.

11. The table II is moved back into its initial position which is flushwith the table I and which declines towards the contact edge 44. Thetable II therefor rises toward the cutting site B in this position fromthe contact edge 44 toward the edge 41.

12. By actuating the conveyor belt 20 the glass sheet shape is advancedtowards the cutting site B.

13. The glass sheet shape is further cut into shapes by the cuttingdevice at the cutting site B.

14. During this cutting process the tables II and III are aligned risingin a plane from the contact edge 44 of the table II toward the edge 50of the table III.

15. To remove the shapes which are formed following the cutting site Bthe table III can be tilted such that it is aligned sloping down fromthe cutting site B toward the edge 50. Using the lifting strips 55 glasssheet shapes can be lifted off the table III and can be alignedessentially vertically.

In the embodiment shown in FIG. 4 in the area of the support surface ofthe table I there is another conveyor device 60. This additionalconveyor device 60 can be used to move the glass sheet to the firstcutting site A in combination with the conveyor device with the conveyorbelt 20 and the suction head 30. The second conveyor means 60 canhowever also be used to move another glass sheet to the cutting site Aat the same time or independently of the transport of a glass sheet bythe conveyor device 20 with the suction head 30 on contact surface 21.

In particular the second conveyor means 60 in the area over the supportsurface of the table I is built as follows: On the beam 62 which ismounted stationary on the table I there is a continuously turningconveyor belt 20 for example in the form of a toothed belt at a distanceover the support surface of the table I with a contact surface 21 whichis aligned essentially normally to the support surface I. Above theconveyor belt 20 on the beam 62 which can be mounted on the one hand onthe table I and on the other on the beam 64 of the cutting site A thereis a guide rail 25 for (at least) one carriage 66. This carriage 66bears at least one suction head 31 which can be lowered onto a glasssheet G which lies on the support surface of the table I (arrow 34).Here the arrangement of the conveyor belt 20 is such that it has adistance from the support surface of the table I which is so great thatthe thickest glass sheet G can be moved through under it.

In order to couple the carriage 66 to the suction head 31 with theconveyor belt 20, on the carriage 66 there is a hydraulic motor 68 whichpresses a plunger 70 against the strand 72 of the conveyor belt 20 whichis adjacent to the carriage 66 so that the carriage moves with theconveyor belt and thus also a glass sheet G on which the suction head 31of the carriage 66 has been placed is entrained.

In order to align a glass sheet G parallel to the direction of motion ofthe conveyor belt 20, there can be lowerable stops 80, for examplecontact pins, which define a “zero line” (reference line) and againstwhich the glass sheet G is brought into contact.

It goes without saying that instead of one carriage 66 with at least onesuction head 31 there can also be two or more carriages 66 each with atleast one suction head 31 in order to enable safe transport of glasssheets G by the additional conveyor means 60 in the area of the supportsurface of the table I.

In one modified embodiment the conveyor means 60 can be adjustableinstead of stationary so that its distance from the contact edge 21which is formed by the conveyor belt 20 can be changed.

In summary, one embodiment of the invention can be described as follows:

-   -   In a system for cutting glass sheets into glass sheet shapes        there is at least one cutting site A, B. In order to align the        glass sheet which is to be cut or the glass sheet shape into a        defined position, on the edge of the tables I and II there are        contact edges 21, 44, 45. In order to move the glass sheets and        the glass sheet shapes into contact with the contact edges 21,        44, 45 the tables I, II are aligned sloping down toward the        contact edges 21, 44, 45 so that the glass sheets and glass        sheet shapes slide on air cushions produced between the glass        sheets or glass sheet shapes and the tables I, II in contact        with the contact edges 21, 44, 45. The glass sheets or glass        sheet shapes which adjoin the contact edges 21, 45 are coupled        by force-fit to the conveyor belts 20 which are provided in the        area of the contact edges 21, 45 and then moved to the cutting        site A, B which is located following the table I, II. When there        are two cutting sites A, B the table II can be inclined between        the two cutting sites A, B such that the intersection point        which is used as the reference point 43 between the two contact        edges 44, 45 is the lowest point of the table II.

1. An apparatus for supporting and cutting glass, comprising: a cuttingdevice; a plurality of support surfaces arranged on opposite sides ofthe cutting device; a first conveyor arranged along an edge of at leastone of the support surfaces, the first conveyor including at least onebelt oriented to contact an edge of a glass sheet positioned over one ofsaid plurality of support surfaces, the first conveyor further includinga drive mechanism for said belt that drives said belt and directly urgesa glass sheet toward said cutting device; and at least one suction headadapted to engage a glass sheet and to urge the glass sheet across atleast one of the support surfaces and into contact with the firstconveyor, so that the first conveyor drives the glass sheet and theattached at least one suction head to a cutting position that allows thecutting device to cut the glass sheet.
 2. The apparatus of claim 1,wherein the first conveyor is aligned normally to the cutting device,the cutting device being adjacent to one of the support surfaces.
 3. Theapparatus of claim 1, wherein the belt comprises a first continuousconveyor belt.
 4. The apparatus of claim 3, wherein the at least onesuction head comprises at least one driver (31) constructed so as to beable to engage a surface of the glass sheet (G) facing away from one ofthe support surfaces and to load the glass sheet against the firstconveyor belt.
 5. The apparatus of claim 1, wherein the at least onesuction head comprises a drive separate from the drive mechanism of thefirst conveyor, for urging an attached glass sheet toward said cuttingposition.
 6. The apparatus of claim 1, wherein the at least one suctionhead does not have its own drive for urging an attached glass sheettoward said cutting position, such that movement of said at least onesuction head toward said cutting position is caused solely by themovement of an attached glass sheet driven by said first conveyor.